import os

import requests
import mimetypes


def download_file(url, local_filename):
    """
    下载文件并保存到本地，基于Content-Type设置文件扩展名。

    参数:
    - url (str): 文件的URL地址。
    - local_filename (str): 本地保存的文件名（不含扩展名）。

    返回:
    - tuple: (完整文件名, 文件类型代码)
             文件类型代码:
                 1 - .docx
                 2 - .pdf
                 3 - .doc
                 4 - 其他
    - None: 下载失败
    """
    try:
        with requests.get(url, stream=True) as response:
            response.raise_for_status()  # 确保请求成功，否则抛出异常

            # 获取Content-Type并猜测文件扩展名
            content_type = response.headers.get('Content-Type', '')
            extension = mimetypes.guess_extension(content_type, strict=False) or '.docx'

            # 分离文件名和现有扩展名
            base, ext = os.path.splitext(local_filename)
            if ext.lower() != extension:
                full_filename = base + extension
            else:
                full_filename = local_filename

            # 下载并保存文件
            with open(full_filename, 'wb') as file:
                for chunk in response.iter_content(chunk_size=8192):
                    if chunk:  # 避免写入空块
                        file.write(chunk)

            # 定义扩展名到代码的映射
            extension_mapping = {
                '.docx': 1,
                '.pdf': 2,
                '.doc': 3
            }
            file_code = extension_mapping.get(extension.lower(), 4)
            return full_filename, file_code

    except requests.HTTPError as e:
        print(f"download: HTTP 错误: {e}")
    except requests.RequestException as e:
        print(f"download: 下载文件时出错: {e}")
    except Exception as e:
        print(f"download: 发生错误: {e}")

    return None

if __name__ == '__main__':
    # 测试下载的URL
    test_url ="http://bid-assistance.oss-cn-wuhan-lr.aliyuncs.com/tender/444d68db95c3438ca481f029500f4f9b.pdf?Expires=1729325467&OSSAccessKeyId=LTAI5tJmL4Nvg95VjgUNvVL6&Signature=2%2Bax895ik7DoFs%2FHVYeN29%2BEiTo%3D&x-oss-process=doc%2Fedit"
    local_file_name = 'C:\\Users\\Administrator\\Desktop\\招标文件\\output\\testdownload'
    downloaded = download_file(test_url, local_file_name)
    if not downloaded:
        print("下载文件失败或不支持的文件类型")
    downloaded_filepath, file_type = downloaded
    print(downloaded_filepath)
    print(file_type)
    # 检查文件类型
    if file_type == 4:
        print("error")